Besides the obvious answer that most anybody who has that kind of money has better things to do with it. . . The obvious answer would be that it would be practically impossible to accurately duplicate the conditions that existed on 9/11. Which is the main reason I believe the conspiracy theories are full of bull puckey. All those arguments re controlled implosion, etc., fall short when you consider that INTENTIONALLY dropping buildings within their footprint requires expert work, planting explosives in a wide variety of locations throughout the buildings, in buildings which are completely empty and idle, thus there are no variations caused by doors opening and closing, HVAC turning on and off, elevators going up and down, etc. INTENTIONALLY obtaining the effect that occurred on 9/11 would have required placing explosives in areas visually apparent to not just the building’s security, but also the inhabitants of the building, linked by elaborate fusing networks, which would have prompted someone to say “Bob, doesn’t that look like, I dunno, plastic explosives taped to the door of the daycare center, and what are those wires going up the stairwell? Perhaps I should call the authorities, or at least take the day off sick.” Merely the random movement of that many human bodies would have SOME cumulative effect on the destructive effects, much less small increments in plane speed, direction, angle of attack, fuel loads, humidity, wind, temperature, etc. The reason a “simulation” would fail to explain anything, and what the conspiracy theories fail to acknowledge, is that sometimes reality happens in amazingly unreal manners, and sometimes apparently suspicious coincidence is merely coincidence. Hey, if you believe humans and the universe can result from an infinite number of random occurrences, then believing 9/11 happened exactly the way it appeared to happen requires very little faith.